Packaging machine



Dec. 5, 1961 Filed June 9, 1960 K. c. BRUGGER 3,011,295

PACKAGING MACHINE 4 Sheets-Sheet 1 INVENTOR. Ken/zei/z (I. Brz yger K. C. BRUGGER PACKAGING MACHINE 4 SheetsSh eet 2 INVENTOR. j H T [(erzrzezlz G Eruyyer BY Dec. 5, 1961 Filed June 9, 1960 Dec. 5, 1961 K. QBRUGGER PACKAGING MACHINE ets-Sheet 3 INVENTOR. Kezzrzei/z LT Bruyyer A figs Filed June 9, 1960 Dec. 5, 1961 K. c. BRUGGER PACKAGING MACHINE Filed June 9, 1960 4 Sheets-Sheet 4 33 I29 I28 5 [55 I54 I53 [55b 1 1 United tates Patent O Filed June 9, H60, Ser. No. 35,085 9 Claims. (Cl. 53-124) This invention pertains to automatic machines for sealing plastic bags and for tightening bags around their content, and then for trimming excess material therefrom.

An automatic bag-tightener and sealer embodying this invention is useful especially in producing compact packages made up of soft articles such as undergarments, sweaters, hose, towels, sheets, pillow cases and other textile products, which have been mounted or folded on a semi-rigid cardboard support. While the invention is particularly suited for use with plastic bags, it may be adapted, of course, for use with other types of bags, and for use with articles of various shapes, sizes and physical characteristics. Such a machine is characterized bymeans such as a horizontal conveyor for transporting article-filled bags having open ends oriented toward the same edge thereof, 7

means such as closely-adjacent portions of the external surfaces of two endless bands moving at the speed of the conveyor for guiding and then pressing together the sides of unfilled end flaps of the bags, means such as cam-guided and actuated mechanical finger units for grasping the end flaps of the bags extending beyond the guiding means and pulling thereon until the bags fit closely around the articles therein, and means such as an elongated, heated element to seal the bags and sever their end flaps simultaneously in close proximity to their contents.

The reasons for having a close fit between a bag and its contents include greater ease in handlingspace conservation, and the preservation of a desired relationship between the walls of the bag and its contents so that printed matter on the former may be displayed effectively. If the bag is transparent, it may be desirable to enhance the display of the contents by preserving, for example, the folds in a folded article, or by preserving a desired interrelationship between multiple articles. These important results may be achieved easily through practice of the teachings of this invention.

Heretofore, several techniques have been used to obtain a close fit between bags and their contents before sealing. For example, bags have been suspended from their open ends and the weight of their contents has tightened the bags therearound to the desired extent. The weightsuspension technique provides a suflicient resolution of the problem in situations where the shape of the packaged articles either is fixed or unimportant. However, this factor is seldom inconsequential and for this reason the method can be used successfully only for packaging fluent materials such as sand, seeds, grains, etc.

Another method which has been applied with some success has entailed the use of plastic bags which are tied loosely around an article to be packaged, and then flashheated to shrink the plastic into a snug fit. This approach, of course, is subject to stringent limitations with respect both to type of articles and the type of plastic bag which can be used. For example, only a bag made of a shrinkable plastic is suitable. This is a serious limitation, for such bags, during aging,-continue to dry out, shrink and harden. Eventually they may become discolored and so brittle that. breakage in handling is a common occurrence, or they may rupture as the result of excessive shrinkage. Furthermore, such bags may be used only with articles which are, unlikely to be harmed while undergoing flash heating.

It should be apparent that the aforedescribed techniques for obtaining a close fit, between bags. and their contents cannot be utilized in packaging many types of articles.

path of movement; two endless flexible, metal bands 3,011,295 Patented Dec. 1961 ice Hence, the weight-suspension technique is unsuitable where a closely-fitting bag is to be utilized to maintain a desired interrelationship between a multiplicity of unconnected items which otherwise would become disarranged during normal handling, or where the folds or relative orientations of a flexible article are to be preserved by the close-fitting sidewalls of a polyhedral bag.

The shrinkage technique likewise would be unsuitable for such application because of the undesirable characteristics of plastic, the criticality of bag size, the diificulty of controlling flash heating closely enough to obtain the required age from a polyhedral bag loosely fitted around contents having the same general configuration as the bag;

3) An automatic machine for forming a compact package made up of a bag and one or more articles in fixed relation thereto;

(4) An automatic bag-tightening, sealing, and flapsevering machine for producing a compact, flexible package from a polyhedral bag loosely surrounding one or more folded flexible articles;

' (5) An automatic machine for tightening a polyhedral bag around flexible contents, and then sealing its end in close proximity to the contents, and severing the excess material, or flap, from the bag adjacent the seal to form a compact, flexible package wherein the contents tend to retain a desired position or arrangement in fixed relation to the bag;

(6 An automatic machine for producing a'compact, flexible package by tightening a loosely fitting pliant plastic container around contents ordinarily disarranged in normal handling until the walls of the container fit closely enough to maintain botha desired arrangement or position of the contents and a desired relationship between container and contents during normal handling, and then sealing the tightly-fitting container in proximity to the contents and cutting away the excess container material; and

(7) An automatic machine for producing a compact, flexible package made up of a folded fabric article normally disarranged in handling but held in position to resist disarrangement by a close-fitting, two-sided transparent plastic bag having printed matter on one side and an unfilled flapend comprising means such as the adjacent external surface of two elongated, endless metal bands constitutinga flap guide for holding the flap ends of the plastic bags in position while cam-guided and actuated mechanical fingers grasp the flaps and pull until the'walls of the bags are drawn closely around the folded articles, and means such as a thermal element for severing the flap and sealing the bag simultaneously. I

An exemplary embodiment of this invention may comprise a conveyor for transporting article-containing bags in a horizontal position with their unfilled flap ends laterally oriented. in the same direction with respect to their mounted one above theother so that the lower external surface of the upper and the upper external surface of thelower are in proximate relation to form a flap guide for the flap ends of the bags, the guide being disposed slightly above the surface of the conveyor; means for driving the metal bands so that surfaces forming the flap guide move in the same direction and at the same speed as the conveyor, whereby the flap ends of the plastic bags may enter, project through and be carried along within the guide without frictional drag thereon, upper and lower positionable guide plates having substantially straight guide edges slightly spaced apart and ex tending for a distance from the entry end of the flap guide to form a slotted section thereof; another upper guide plate and a series of lower resiliently-loaded guide plates having upper guide edges opposite the guide edge of the other upper plate for pressing together under predetermined and adjustable tension the remainder of the proximate surfaces of the metal bands to form a clamping, or tightness-retaining, section of the flap guide; a bag-tightening mechanism made up of an elongated continuous chain mounted on rotatable sprockets so that the upper side of the chain travels along a path opposite the slotted section of the flap guide; means for driving the chain in the same direction and at the same speed as the conveyor and the endless metal bands, a series of resiliently-closed, horizontally-oriented and laterally-reciprocable mechanical finger units mounted at spaced intervals on said chain, a first cam for opening said finger units, opposite the entry end of said slotted sections, whereby one of said fingers will leave the first cam and close to grasp the plastic near the forward side of the bag flap projecting through said slot, and after the bag is carried along for a short distance by the conveyor and the metal bands of the guide, a successive finger will be opened by said first cam to close and grasp the flap near its rear side, a second cam to reciprocate the finger units away from the flap guide so that the plastic bag is tightened around its contents, a third cam to open the fingers and release the bag flaps after they have left the slotted and entered the clamping section of the flap guide, and a fourth cam to reciprocate the finger-pairs once again into close proximity to the entry end of the flap guide; and an electrically-heated wire closely spaced from and sloping upwardly across the edge of the clamping section of the flap guide to sever the flaps and seal the bags.

The foregoing paragraphs are intended to summarize and explain the significance of this invention in relation to the problem which it resolves, and should not be construed to narrow the scope of protecting delimited by the claims set forth hereinafter. For a more complete understanding of the structure, operation, and novel features of a preferred embodiment of the invention, consider the following description with reference to the drawings wherein:

FIGURE 1 is a front elevation of an automatic bagtightening and sealing machine in accordance with this invention representing diagrammatically the conveyor, the guide plates and endless metal bands of the flap guide, the power source and drives, and portions of the supporting structure;

FIG. 2 is a plan view of the machine showing diagrammatically the entry guides for the flap ends of the bags, the outline of the bag-tightener and sealer stages and the section of the conveyor adjacent thereto;

' FIG. 3 is a rear elevation of the machine representing diagrammatically the principal operating components of the tightening and thermal-sealing stages, the vacuumtype waste collector, the power source and drives, and portions of the supporting structure;

FIG. 4 is a front elevation of the machine with the conveyor removed to show in greater detail various features of the endless metal bands and guide plates making up the flap guide, the drives for the metal bands, and other structural details;

FIG. 5 represents the tightener stage as viewed along a transverse plane therethrough showing various structural details of the conveyor and the tightener mechamsm;

FIG. 6 is a plan view of the bag-tightener mechanism representing the chain and mechanical finger assembly, the finger-opening cam at the grasping end of the mechanism, a portion of the upper cam for reciprocating the closed fingers horizontally away from the flap guide to achieve tightening action, and in a cutaway section, a portion of the lower cam for reciprocally shifting the fingers into grasping position toward the flap guide:

FIG. 7 represents one of the mechanical finger units of the bag-tightening mechanism showing its closed position in solid lines, its open position in dotted lines, and a cutaway view of the resiliently-loaded pin maintaining the finger unit in a normally-closed position, and the opening pin by which the finger may be cam-actuated into open position; and

FIG. 8 is a transverse section through the sealing and cutting stage showing a bag already tightened and firmly gripped in the clamping section of the flap guide being sealed and severed by the thermal element.

As represented in FIGS. 1 and 2, a bag-tightening and sealing machine in accordance with this invention generally may comprise a undirectional, endless, horizontal-surface convyer 1 for transporting a plurality of article-containing bags 2 having unfilled end flaps 2a, a flap guide 3 having a slotted section 3a, and a clamping section 3b for supporting and carrying end flaps 2a in a position facilitating tightening, severing and sealing operations, an adjustable transverse guide 27 (FIG. 2) for positioning the bags 2 on the conveyor 1 so that their end flaps 2a are in substantial alignment, a bypass guide 5 to insure that the end flaps 2a pass the upright support 4-1 without undue wrinkling or folding, a bag-tightener stage 7 (FIG. 2) for grasping and pulling on the end flaps 2a projecting through the slotted section 3a of the flap guide 3 in order to tighten the bag around the articles contained therein, a sealer stage 8 for thermally severing the end flaps 2a projecting through the clamping section 3b of the flap guide 3 and simultaneously sealing the severed bag ends, and a motor 9 and chain and sprocket assemblies it), 11, and 12 for operating the conveyor 1 the tightener 7 and the flap guide 3, respectively, at equal speeds in the direction indicated by the arrows.

PHYSICAL DESCRIPTION With reference principally to FIGS. 1 and 2, the conveyor 1 is made up primarily of an elongated table 13 supporting a translator mechanism 14. When in use, article-containing bags 2 are loaded onto the right end of the conveyor 1 and are pushed along the smooth surface of table covering 13a by the translator mechanism 14,

The translator mechanism 14 comprises front and rear endless chains 15 and 16 of equal length. The front chain 15 engages front drive sprocket 17 mounted on drive shaft 19 and front idler sprocket 18 mounted on idler shaft 20 to form an elongated loop having an upper horizontal segment 15a supported in subjacent relation to the upper front edge of table 13 on the horizontally projecting side of angle iron 21. The vertically-projecting side of angle iron 21 extends for a short distance above the surface of table 13 to form a guard rail 22. In like manner, rear chain 16 engages a rear drive sprocket 23 (FIG. 3) and a rear idler sprocket (not shown) mounted on the rear ends of drive shaft 19 and idler shaft 20, respectively, so that the rear chain 16 forms an elongated loop having effectively the same shape as that of the front chain 15. The upper horizontal segment 16a of rear chain 16 is supported in subjacent relation to the upper rear edge of table 13 on the rearwardly-projecting side'of rear angle iron 24. In this instance, however, the upper edge of the rear angle iron 24 is below or aligned with the covering 13a of table 13 to avoid obstructing transverse movement of the bags 2 during the bag positioning and tightening operations.

To provide means for imparting translatory motion to bags in the direction of the arrows, generally-rectangular pusher bars made of sheet metal or other appropriate, material are coupled in transverse and uniformly spacedapart relation to front and rear chains 15 and 16, respectively. Each of the pusher bars 25 has a rectangular cutout 26 adjacent its lower front corner to provide a space for accommodating guard rail 22, and an adjustable transverse guide 27 to be described more fully hereinafter. The lower edges of the pusher bars 25 may lightly engage or be closely spaced from the smooth covering 13a of table 13 (FIG. to minimize the likelihood that folds of bags 2. may become wedged therebetween. The longitudinal spaces between pusher bars constitute pockets 28 large enough to accommodate article-containing bags 2 of the largest size expected to be processed by the machine. The translator mechanism 14 may be driven, for example, by motor 9 coupled thereto by an endless chain 29 extending between one of the sprockets (not shown) of motor sprocket assembly 30 and a rear sprocket 23 (FIG. 3) on the rear end of drive shaft 19.

The elongated table 13 provides a stationary horizontal supporting surface for bags 2 during their passage through the machine. As indicated in FIG. 1, this table extends to the right far enough to enable each successive pocket 28 of the conveyor 1 to be loaded with an articles.

containing bag 2 before it arrives alongside the bagtightener stage 7. As shown in FIG. 2, the table 13 has a substantially rectangular top- 13b provided with a smooth cover 13a made of a material characterized by low frictional drag on bags 2. The table top 13b is fastened by any suitable means to framing members 130,

and is supported horizontally at a convenient working level on metal front and rear (not shown) legs 13d at n the entry and discharge ends, and wooden front and rear (not shown) legs 13a intermediate thereto. The drive shaft 19 of the translator mechanism 14 is rotatably supported in a pair of journals 32, which in turn, are mounted in a pair of brackets 33 projecting from the discharge end of table 13. In like manner, the idler shaft 24'; is rotatably mounted in apair of journals 34 within a pair of brackets 35 projecting from the entry end of table 13. -The brackets 33 and 35 are supported by the legs 13d attheir respective ends of the table 13. Inasmuch as the table structure is conventional, some details.

such as fasteners and reinforcing members havebeen omitted to avoid cluttering the drawings unnecessarily. The table top 13b, the framing members 130, and the intermediate legs 13a may be made of wood. However, the end legs 13d and support brackets 33 and 35 are made of channel iron to provide sufficient strength to support the drive and idler shafts 19 and 20, and the weight of the return flight 36 of front and rear conveyor chains 15 and 16, respectively.

The adjustable transverse guide 27 (FIGS. 2 and 5) insures that each of the bags 2 is in correct lateral position on the top of table 13 as its end flap 2a enters the bag-tightener stage 7. As represented best in FIG. 2, the transverse guide 27 may constitute a flat strip of resilient metal having one end 27a fastened to the posterior surface of guard rail 22 so that one edge of the strip rests.

against the upper surface of the table 13, and its front surface normally lies flat against the rear surface of guard rail 22. The width of the metal strip is selected to be slightly less than the vertical dimension of the. rec-r tangular cutouts 26 in the pusher bars 25, and its length is chosen so that its free end may be, separated a predetermined distance from its normal position against the rear surface of guard rail 22 to form agently-inclined surface for engaging the front; ends of bags 2, and urging them toward the rear edge of table 13 until their end flaps 2a are positioned for proper entry into the bagtightener stage '7. The lateral, slope of transverse guide 27 may be adjusted as required to accommodate articlecontaining bags 2 of differing lengths merely by sliding the wedge 37 longitudinally toward or away from. the.

point 27a where the guide is fastened to guard rail 22.-

As shown in FIG.-3, the bag-tightener stage 71 and lar metal base plate 38. The base plate 38, positioned so that its longer axis is horizontal, is secured, in turn, with bolts 39 to upright channel shaped supports 40 and 41. The lower ends of upright supports 40 and 41 are mounted on horizontal base pieces 42 and 43, respective,- ly. The stability of the resulting structure may be en-- hanced in conventional fashion by securing reinforcing members (not shown) between the ends of base-pieces 42 and 43, and points thereabove on upright supports 41 and 42, respectively. v

The base plate 38 is provided with a horizontal slot 44 midway between its upper and lower edges, extending from one end for a distance equal to-the combined lengths of the bag-tightener and sealer stages 7 and 8, respectively. The slot 44 has an enlarged entrance section 44a so that the end flaps 2a easily may enter the slot 44 without becoming misshapened.

The dimensions of the base plate 38 and the upright supports 40 and 41 are chosen so that the flap guide 3, the bag-tightening stage 7, and the sealer stage 8 may be positioned in cooperative relation with the rear edge of conveyor table 13. A guide 5 is secured to upright support 41 adjacent to the entry end of flap guide 3 to insure that the end flaps 2a extending beyond the rear edge of table 13 will not be deranged asthey pass thereby.

The llap guide 3 insures that the end flaps of bags. 2 will be carried and maintained in a position facilitating the bag-tightening, trimming and sealing operations. As shown in FIGS. 4 and 5, the flap guide 3 is spaced above and in parallel relation to the surface of conveyor table 13. This arrangement causes the flap ends 2a to be, raised off the surface of table 13 during the bag-tightening operation, thereby minimizingjany tendency of the bags 2 to become twisted by frictional drag between their lower sides and the surface of table cover 13a, As a result, it is less likely that, resulting sealed edges on the flap ends 2a will be disaligned with respect to the opposite end edges of the bags 2.

upper and lower endless metal bands 45 ,and- 46, respectively, rotatably mounted on base plate 38 so that a lower horizontal segment 45a of the upper and an upper horizontal segment 46a of the lower will have normally adjacent external surfaces forming a slot, having moving sides for carrying the flap ends of bags 2; a first, upper guide plate 47 and a first lower guide plate 48 for establishing the slot width of a slotted section 3a of the flap guide 3, and a second upper guide, plate 49 and a series of resiliently-mounted lower plates 50 opposite thereto for holding a portion of the lower band,

segment 46a in contact with an adjacent portion of the upper band segment 45a to form the clamping section 3a of the flap guidev 3.

The lower metal band 46 is supported: in parallel relation to the front surface of base plate 38 by lower driving pulley 51 and. lower idler pulley 52 mounted for rotation around shafts 53 and 54, respectively. The upper metal band 45 also is supported in parallel relation to the front surface of base plate 38 on upper drive pulley 55 and upper idler pulley 56 mounted for rotation on shafts 57 and 58, respectively. The lower metal band 46 is rotated so that its upper horizintal segment; 4.6a travels. in the same direction and at the same speed as conveyor 1 by a motor 9 coupled to lower drive pulley 51 by an endless chain 59 provided between motor sprocket assembly 30 and a procket 60 mounted on the shaft 53 of lower drive pulley 51. The upper drive pulley 55 is coupled to lower drive pulley Sljby gears 61 and- 62 having a one-to-one ratio so that the band segment 45a, also travels in the same direction and at the same. speed as conveyor 1. Accordingly, the adjacent surfaces of the upper and lower band segments 45:; and 46a, re-

spectively, are driven in the same direction and at the same speed as bags 2 on conveyor 1, thereby providing a drag-free means for carrying the end flaps 2a through the fiap guide 3.

The first upper guide plate 47 and the first lower guide plate 48 are provided with vertically-oriented elongated holes 63 to accommodate bolts 64 for securing them in position against the front surface of base pltae 38. The elongated holes 63 make it possible to adjust the vertical positions of these plates relative to the slot 44 in base plate 38 and to each other. The second upper guide plate 49, mounted in end-to-end relation with the first upper guide plate 47 on the front surface of base plate 38 by bolts 65, also is provided with elongated holes 66 for adjusting its vertical position to efiect an alignment of its lower edge with that of the first upper guide plate 47. The series of lower guide plates 50 are supported slidably against the front surface of base plate 38 below the second upper guide plate 49, and in end-to-end relation with each other and the first lower guide plate 48 by bolts 67 accommodated in vertically-oriented, elongated holes 68. Each one of the series of lower guide plates 50 is biased resiliently by coil springs 69 to thrust upwardly until its upper edge presses together the lower and upper band segments 46a and 45a, respectively, against the lower edge of the second upper guide plate 49, thereby forming the clamping section 36 of the flap guide 3. The lower ends of the coil springs 69 are secured to the base plate 38 by bolts 70, and their upper ends rest against cradles provided on the upper ends of spring mounts 71 for engaging the respective lower edges of the series of guide plates 50.

' As shown in FIGS. 4, 5, and 8 the adjacent front edges 72 and 73 of the first upper and first lower guide plates 47 and 48, respectively, are beveled to avoid the likelihood that the bags 2 may be cut or torn thereby during the tightening operation. Likewise, the adjacent front edges of the second upper guide plate 49 and the series of lower guide plates 50 also are beveled for the same reason. In addition, the adjacent rear edges of the first upper and the first lower guide plates 47 and 48 are provided with vertically-extending shoulders 74 and 75, respectively, from being displaced rearwardly from their paths along edge surfaces 76 and 77 by the drag thereon which may result from pulling of the end flaps 2a during the bag-tightening operation.

The width of the slotted section 3a of the flap guide 3 should be adjusted to permit the folds of the end flaps 2a to slide easily therethrough during bag-tightening, but to restrain any portion of the bag contents from becoming wedged between the upper and lower metal band segments 45a and 46a, respectively. Moreover, the clamping section 3b of the flap guide 3 should be adjusted to be colinear with the slotted section 3a and to have sufficient tension to hold the end flaps securely, thereby maintaining the tightness of the bags 2 during the flap-trimming and bag-sealing operations performed by sealer stage 8.

The upper and lower guide pulleys 78 and 79, respectively, mounted rotatably on shafts 80 and 81, respectively, secured to and extending forwardly from base plate 38 adjacent the entry of the flap guide 3, establish a gentle convergence of the band segments 45b and 46]) from idler pulley 56 and 52, respectively. Hence, the upper and lower sides of the end flaps 2a are engaged and gradually pressure together by the convergence of band segments 45b and 46b until they enter the slotted section 3a. In addition to the aforementioned guides, the upper and lower entry guides 82 and 83, respectively (FIG. 3), are secured to the rear surface of base plate 38 opposite the entry end of the slotted section 3a where the bag-tightening operation begins. The entry guides 82 and 83 are provided with opposing curved edges 82a and 83a converging from a maximum spacing at their entry ends to form a short guide slot 84 having approximately the same width as the slotted section 3a. Hence, the end flaps 2a are supported and prevented from drooping out of the position required for proper entry into the bag-tightener stage 7.

Between the discharge end of the flap guide 3 and the upper and lower drive pulleys 55 and 51, respectively, the upper and lower metal band segments 45c and 46c, respectively, diverge to insure their complete disengagement from bags 2. A vertical guard plate 85 is secured to the rear edge of conveyor table 13 opposite the meshing gears 62 and 61 intercoupling the lower and upper drive pulleys 55 and 51, respectively, to make certain that the tightened and sealed bags will not become caught and mutilated therein.

The bag-tightener stage 7 (FIGS. 3, 5 and 6) supported on the rear surface of base plate 38, generally comprises a plurality of finger units'100 secured in spacedapart relation on an endless chain 101 having an upper horizontal segment 101a adjacent and parallel to the slotted section 3a of flap guide 3, a drive sprocket 102, and drive chain 103 for rotating the endless chain 101 in the same direction and at the same speed as the end flaps 2a extending rearwardly through and carried by the slotted section 3a, and cam surfaces for opening and closing the finger units to grasp the end flaps 2a, to reciprocate the finger units 100 rearwardly and tighten the bags 2 around their contents, to open the finger units 100 when the end flap 2a leave the slotted section 3a and enter the clamping section 36 of the flap guide 3, and to reciprocate the finger units 100 forwardly again into grasp-ing position as they travel along the return flight 101!) of endless chain 101.

The endless chain 101 is supported by a drive sprocket 102 and an idler sprocket 104 mounted for rotation on drive shaft 105 and idler shaft 106, respectively, secured, in turn, in rearwardly-extending relation to base plate 38. Supported in this manner, the endless chain 101 forms an elongated loop parallel to the rear surface of base plate and having an upper segment 101a adjacent and generally parallel to the slotted section 30 of flap guide 3 and a return flight 101b. The endless chain 101 is rotated to impart linear motion to the upper segment 101a in the same direction and at the same speed as the conveyor 1 by a motor 9 coupled in any conventional manner via, for example, a sprocket (not shown) of the motor sprocket assembly 30 operating through an intermediate sprocket assembly 107 and drive chain 103 to rotate a receiving sprocket (not shown) mounted on drive shaft 105 and coupled in driving relation to drive sprocket 102.

A plurality of finger units 100 are mounted slidably in brackets 108 secured in uniformly spaced-apart relation to endless chain 101. The brackets 108 are oriented transversely with respect to the direction of motion and extend outwardly from the outer periphery of endless chain 101. Each bracket 108 is provided with detent holes 109 and 110 (FIG. 7) for engaging a resilientlymounted detent 111 provided in the base finger 112 of each of the finger units 100, thereby establishing limits for their reciprocal motion.

Each of the finger units 100 (FIG. 7) is made up generally of a base finger 112 having one end coupled fixedly to one side of hinge block 113, and a normally-closed clamping finger 114 having one end pivotally mounted on the opposite side of hinge block 113 and a grasping end 115 swingable through a predetermined are away from the grasping end 116 of the base finger 112.

Two opposite sides of the hinge block 113 are slotted to form rectangular recesses 117 and 118 (FIG. 3) for receiving the base and clamping fingers 112 and 114, respectively. The bottom of recess 118 is provided with a surface 119 (FIG. 7), which slopes downwardly and rearwardly, for permitting the movement of the rear end of the clamping finger 114 as it swings into open position as indicated by the dotted lines 120 of FIG-7.

The rear end of clamping finger 114 is pivotally secured in recess 118 by a pivot pin 121 accommodated in holes 122 provided therefor. A biasing spring 123 and pin 124 are disposed in a bore 125 provided in the slop ing surface 119 of hinge block 113 to maintain the grasping end 115 of the clamping finger 114 in normallyclosed position again-st the grasping end 116 of the base finger 112. A slidable actuating pin 126, provided in a hole 127 extending between the truncated sides of the hinge block 113 bears against the underside of the clamp ing finger 114 in front of the axis of-pivot pin 121 and has one end 126a normally extending a short distance beyond the underside of the base finger 112. As a result, sufiicient force exerted in the axial direction against the extending end 126a while the base finger 112 remains unyielding will open the grasping end 115 of spring-biased clamping finger 114 through an are determined, within limits, by the length of the extending .end 126a.

The grasping end 116 of the base finger 112 is provided with an adjustable claw 128 having a recess 129 and external threads on its outer surface to engage the mating internal threads of mounting hole 130. The grasping end 115 of clamping finger 114 also is provided with an adjustable claw 131 having external threads for engaging the mating internal threads provided in its mounting hole 132. However, unlike claw 128 the claw 131 of the grasping clamping finger 114 has a needlelike projection 133 mating with the recess 129 of claw 128 for penetrating the end flaps 2a and holding on to them firmly during the tightening operation.

To open finger units 100 as they travel into grasping position opposite the entry end of the flap guide 3, a cylindrical cam 150' is coupled to the rearward side of idler sprocket 104 for rotation therewith. Hence, as each finger unit 100 begins its clockwise trip around the axis of idler sprocket 104, the extending end 126a of the actuating pin 126 of each finger unit 100 engages the surface of cylindrical cam 150 and is forced upward thereby to open clamping finger 114. A cylindrical support 151 is coupled to the front side of idler sprocket 104 for rotation therewith in order to provide a supporting surface to prevent the grasping ends of the finger units 100 from being rotated around endless chain 101 into a downwardly tiltedp'o'sition relative to the end flap-s 2a by the force exerted on the actuating pin 126 when it comes into engagement with the surface of cylindrical carn 150. A similar cylindrical cam 152 and cylindrical support (not shown) are coupled to the drive sprocket 102 to open finger units 100 and release the end fiaps 2a after they have entered and are held securely by the clam-ping section 35 of the flap guide 3.

As the finger units 100 disengage the surface of cylindr-ical actuating earn 150 and begin traveling along the upper horizontal segment 161a, the clamping finger 114 of each successive unit returns to its normally closed position under the influence of its biasing spring 123 thereby firmly grasping an end fiap 2a at a point close to the rear surface of the flap entry guides 82 and 83.

The finger units 100 are reciprocated rearwardly to tighten the bags by a cam 153 secured by bolts 154 to the rear surface of base plate 38 in a position so that it engages the grasping end 116 of the base finger 112 of each of the finger units 100. The cam surface 155 of cam 153 has a rearwardly sloping section 155a, a parallel section 155b, and a forwardly sloping section (not shown). Hence, each of the finger units 100 first will engage the rearwardly sloping section 155a shortly after it has grasped one of the end flaps 2a. As each finger unit 100 moves along the rearwardly sloping-section 15512, the end flap 2a is pulled rearwardly, thereby tightening the bag 2 around its contents. When the finger unit 160 reaches the parallel section 155b of cam 153, the detent 111 snaps intodetent hole 109 of bracket 108 and maximum tightness of the bag 2 has been achieved. This degree of tightness is maintained by the parallel'section 10 155b of cam 153 until the end flap 2a enters the clamping section 3b of flap guide 3. At this point, the finger units leave the parallel section 15517 of cam 153 and begin traveling along the forwardly sloping section (not shown) until the tension on the end flap 2a is relieved sufiiciently to facilitate opening of the finger units.

A rearwardly-extending horizontal bracket 156 is secured by bolts 157 (FIG. 5) to the base plate 38 to provide support for a vertical guard plate 158 located rearwardly of the finger units 100 traveling on the upper segment of endless chain 101 and a chain guide bracket 1-59 to prevent sagging from the weight and rearward bending of the upper segment 10111 as the result of the lateral force exerted thereon by the action of cam 153;

After opening and releasing the end flaps 2a upon engagement with the cylindrical actuating cam 152, the finger units 100 are carried on endless chain 101 clockwise around drive sprocket 102 until they leave actuating cam 152 and begin their return flight 10117 to idler sprocket 104. At this point, each finger unit 100 closes once more under the influence of its biasing spring 123.

To reciprocate each finger unit forwardly so that'it will be in proper grasping position when it arrives once more opposite the flap entry guides 82 and 83, a rearwardlyextending horizontal bracket 160 is secured by bolts'161 to base plate 33. iAt the rear end of bracket 160 a cam 162 mounted on spacing member 163 is secured by bolts 164 in a position where its forwardly-facing cam surface 165 will engage the hinge block 113 of each of the finger units 100 and reciprocate it forwardly until the detent 111 snaps into position in the forward detent hole of its mounting bracket 108. The cam surface 165 has a forwardly-sloping section 165a and a parallel section 16517. To prevent forward bending of endless chain 101 caused by'the lateral pressure exerted by the action of cam 162 against finger units 100 as they travel along on the return flight 16112, a chain guide .166 is secured beneath bracket by bolts 167.

The sealer stage 8, mounted on the base plate 38 below and behind the clamping section 312 of flap guide 3, simultaneously severs the end flaps Zn from bags 2 after tightening, and then seals the severed edges to produce compact packages. With reference principally to FIGS. 3 and 8, the sealer stage 3 comprises an elongated thermal'elernent 200 mounted on an adjustable support plate 201 secured to the rear surface of base plate 38 with bolts 202 in a' position below and behind the clamping section 3b of the flap guide 3. The bolts 202 are accommodated in a front transverse slot 203 and a rear transverse slot (not shown) provided in the support plate 201 so that the angle and spacing of the plate relative to the clamping section 3b may be adjusted until thermal element 200 is inclined slightly upwardly in the direction and across the path of travel of end flaps 2a at the angle required for optimum operation of the sealer stage 8.

The elongated thermal element 200, made of a suitable length of Nichrome wire or other material having the requisite electrical and structural characteristics is suspended under tension between angular terminals 204 and 205 made of an electrically-conductive material such as copper or brass. The angular terminal 204 is mounted in fixed position by any suitable means on a rectangular insulator 206 secured by bolts 207 to the end of support plate 201 adjacent the discharge end of bag-tightene'r' stage 7. The angular terminal 205 is secured to a cylindrical insulator 208 by screws 209. The cylindrical insulator 208 has a hole 210' centrally disposed therein to accommodate a bolt 211 which holds it rotatably on the other end of support plate 201. A coil spring 212 is secured in any conventional manner under tension between a point near the upper periphery of cylindrical insulator 208 and the support plate 201 to exert a continuous torque tending to rotate the insulator 208 in the clockwise direction, thereby providing a resilient bias to compensate for.

anytendency of the thermal element 260 to expand linear- 1 1 ly and sag after it becomes hot. The thermal element 200 is heated to the temperature required to melt through the plastic end flaps and seal the severed edges by applying an electrical potential from a source (not shown) via conductors 213 and 2 14 extending from junction box 215 to the angular terminals 204 and 205, respectively.

The suction end of a flexible conduit 216 leading to a vacuum machine (not shown) is held in position beneath the thermal element 201) to collect the severed portions of end flaps 2a by a. bracket 217 secured, in turn, by bolt 218 to base plate 38.

After trimming and sealing in sealer stage 8, the sealed bags are translated for the remaining distance to the end of conveyor table 13 where they may be discharged into a bin (not shown) or otherwise collected and removed. A curved discharge plate 220 is secured to the discharge end of the table 13 to provide a supporting surface for the table 13 to providea supporting surface for the bags in pockets 28 as the pusher bars 25 leave the end of the table 13 and begin moving around front and rear drive sprockets 17 and 23, respectively. As the pockets 28 become ver tical and begin to invert, the sealed bags drop from the conveyor under the influence of gravity.

Inasmuch as some of the structural details of the aforedescribed embodiment may be in accord with numerous design variations well known to the prior art, they have been omitted. For example, the details of the rotatable mountings for the various pulleys and sprockets would result in cluttering the drawings and lengthening the text to an extent out of proportion to their contribution to an undertaking to practice this invention. Hence, it is immaterial, for example, whether the shafts are mounted in their supporting structures to rotate with the sprockets or pulleys supported thereon, or whether they are designed to be stationary with the sprockets and pulleys being provided with the bearings required for rotation. Likewise, the various structural details of the source of motive power and the chain and sprocket drives also are conventional and have been omitted. Moreover, where a plurality of identical structures is present, further simplification and clarification of text and drawings has been achieved by describing and portraying only one thereof.

Operation The operation of the aforedescribed embodiment of a bag-tightener and sealer machine in accordance with this invention will be explained in the order of the functions performed from the time a loose-fitting article-containing plastic bag 2 having an unfilled end flap 2a is placed on conveyor 1 until it is discharged as a compact package.

It should be understood, of course, that a machine in accordance with this invention will be provided with appropriate switchgear to control starting, stopping and the speed of operation. In addition, signal lights representing various normal operating conditions as well as important malfunctions also may be provided in accordance with standard electrical practices. To stop the machine automatically when the end flap 2a of a bag 2 improperly enters the clamping section 3b, interlocking control circuitry may be installed. This may be done merely by mounting a single-pole snap-action switch, connected in a well-known manner in the power supply circuit of motor 9, at a location adjacent the lower edge of the first of the series of resiliently-mounted lower guide plates 59. Hence, when an improperly folded or misshapen end flap 2a enters the clamping section 3a, the first of guide plates 50 will be pushed downward, thereby actuating the control arm of the switch to disrupt the circuit to motor 9 and energizing an appropriate signal before serious damage results. Many other interlocking controls and circuit possibilities for signal lights will occur readily to persons skilled in the art who undertake the practice of theinvention.

Assume that the machine is operating normally. A loosely-fitted, article-containing plastic bag 2 is placed in one of the pockets 28 of conveyor 1 with its unfilled end flap 2a extending toward the rear edge of table 13. The trailing edge of bag 2 is then engaged by the pusher bar 25 comprising the trailing edge of pocket 28 and translated along the top of table 13 in the direction of the arrows.

As the bag 2 moves along the conveyor 1, the first operation performed upon it makes certain that it is positioned properly for entering flap guide 3. This result is accomplished by adjustable transverse guide 27 (FIGS. 2 and 5) which acts upon the forward end of bag 2 to push it rearwardly until the end flap 2a slightly overlaps the rear edge of table 13. The end flap 2a is protected by by-pass guide 5 from becoming misshapened as it passes the upright support 41. Just beyond by-pass guide 5 the end flap 2a enters the enlarged section 44a of the slot in base plate 38. At the same time, the transverse guide 27 is pushing bag 2 rearwardly to thrust more of end flap 2a through the slot 44a.

As the bag 2 moves further, the end flap 2a comes into engagement with the converging segments 45b and 46b of the upper and lower metal bands 45 and 46, respec tively, driven via motor 9 and the chain and sprocket assembly 12 in the same direction and at the same speed as conveyor 1. Thenceforth, the metal bands 45 and 46 carry the end flap 2a through flap guide 3 without drag. As the end flap 2a engages the converging segments 45b and 46b of the metal hands, it also begins its entry into the slot 84 between flap entry guides 82 and 83 (FIG. 3).

In this manner, the bag 2 and its end flap 2a are positioned properly and carried into the slotted section 3a of the flap guide. Once within the slotted section 3a of the flap guide, the bag-tightening operation begins. The portion of flap guide 2a extending through slot 44 of base plate 38 is positioned vertically to be grasped properly on its leading side adjacent the slot 84 by one of the finger units 101) of bag-tightener stage 7 .7 This action occurs as finger unit 1%, moving an endless chain 101 in the same direction and at the same speed as end flap 2a, leaves the surface of cylindrical actuating cam (FIG. 6), thereby enabling its actuating pin 126 (FIG. 7) to extend and permitting the clamping finger 114 to respond to the resilient force exerted by coil spring 123 and return to its normally-closed position on base finger 112. The endless chain 101 is driven by motor 9 in a clockwise direction via the intermediate sprocket assembly 107 and the chain and sprocket assembly 11. As the end flap 2a of bag 2 moves further along in the slotted section 3a of the flap guide, another of finger units 100 operates in the manner described above to grasp the trailing side of end flap 2a.

When the end flap 2a is grasped securely by finger units 100, they are reciprocated rearwardly in their mounting brackets 103 by the surface of cam 153 (FIGS. 6 and 7) until detent 111 (FIG. 7) snaps into the forward detent hole 110, thereby tightening around its contents by pulling its end flap 2a through a distance predetermined by cam 153 and detent hole 110. The slotted section 3a of the flap guide is wide enough to permit the end flap 2a to slide transversely with respect thereto, but narrow enough to prevent any portion of the contents of the bag from becoming wedged therein.

The cam 153 maintains the finger units 1% in their rearwardmost position until the end flap 2a enters and becomes firmly gripped within the clamping section 3b of flap guide 3. When this occurs, a forwardly-sloping.

section (not shown) of earn 153 releases the pulling tension on end flap 2a. Shortly thereafter, the finger units 100 are opened as the extending ends 126a (FIG. 7) of their actuating pins engage the surface of cylindrical actuating cam 152. After releasing the end flap 2a, the fingers 100 continue their travel around cylindrical actuating cam 152 until they begin their horizontal return flight 10111 (FIGS. 3, 5 and 6). During the horizontal return flight 191b, the fingers 100 are in their normallyclosed position and are forced forwardly by the engagement of their hinge blocks 113 with the surface of cam" 109. When this occurs, the fingers 100 once againare prepared to grasp the end fiap of another bag as it comes into position therefor on cylindrical actuating cam 150.

After their release by fingers 1%, the end flap 20, held tightly within clamping section 312 of flap guide 3 moves into contact with the thermal element 200 of sealer stage 8. The thermal element 200 melts the plastic material of the end flap 2a, thereby severing it from the main body of bag 2 and sealing the severed edges to, produce a compact package having desirable shape-retentive properties. The severed end flap is sucked into the opening of the conduit 216 leading to a vacuum machine (not shown). 7

After sealing, the bag 2 leaves the clamping section 311 of flap guide 3 and is carried on conveyor 1 until it is discharged from the end thereof by gravity.

It should be noticed that the uniform longitudinal dimensions of pockets 28 of conveyor 1 and the uniform spacing between finger units 100 on endless chain 101 are selected so that the aforedescribed operations will be performed automatically, on bags placed in each one of the successive conveyor pockets 28.

The representations in the drawings and foregoing text are intended merely to facilitate the practice of this invention by persons skilled in the arts pertaining thereto. The scope of the invention is delineated in the following claims:

What is claimed is:

1. An automatic bag-tightening and sealing machine comprising: means for transporting bags containing articles to be packaged, said bags having unfilled end flaps extending laterally in the same direction with respect to the path of motion; means disposed along one side of said transporting means for grasping and pulling said flaps to tighten said bags around said articles; and means disposed end-to-end with respect to said grasping and pulling means for maintaining tightness of said bags during further travel along said transporting means; means disposed adjacent to said grasping and pulling means for sealing said bags and trimming said flaps; and a source of motive power coupled respectively to said transporting, grasping and pulling, and tightness-maintaining means,

2. An automatic bag-tightening and sealing machine comprising: a conveyor for transporting article-filled,

, loosely-fitted bags having unfilled end flaps extending in the same direction; first means disposed vin the path of said end flaps for grasping and pulling on said flaps'to tighten said bags around said articles; second means disposed in the path of said end flaps to sever said end flaps and seal said bags; and third means disposed between said conveyor and said first and second means for positioning and carrying said end flaps and for restraining movement of said articles during operation of said first means, and for positioning, carrying andclamping the end flaps after bag-tightening to faeilitate operation of said second means; and means for driving said conveyor, said first means, and said third means in the same direction and at the same speed.

3. An automatic bag-tightening and sealing machine comprising: means for transporting bags containing articles to be packaged, said bags having unfilled end flaps extending laterally in the same direction with respect to the path of motion of said transporting means; means disposed along one side of said transporting means for tightening said bags around said articles; means supported between said transporting means and said tightening means for guiding said flaps, said guiding means including first means having a slotted section for supporting said flaps loosely to facilitate the operation of said bag-tightening means, second means constituting a resiliently-loaded clamping section for maintaining the i4 tightness of said bags during subsequent bag-sealing and flap-trimming operations, and third means for. positioning and; carrying said flaps through said first and second means; means disposed alongside the clamping section of said guiding means for trimming said flaps and sealing said bags; and a source of motive power coupled respectively to said transporting means,- said third means of the guiding means, and said tightening mechanism for driving the three last-named means in the same direction and at the same speed.

4. An automatic bag-tightening and sealing machine comprising: an endless conveyor for transporting looselyfitted, article-containing bags having unfilled end flaps extending in a direction transverse to the path of said conveyor; a vertical support plate disposed alongside a portion of the side of said conveyor nearest said end flaps, said support platehaving a horizontal slot disposed effectively at conveyor level; means mounted on said plate for guiding said flaps into and through said slot, said guiding means including first means having a slotted guide section for loosely supporting said flaps and second means in end-to-end relation with said first means constituting a resiliently-loaded clamping section, said guiding means further including upper and lower elongatedbands rotatably mounted in'the same plane so that theloWer side of the upper and the upper side of the lower of said bands are in longitudinal and slidable relation with the respective sides of said slotted and clamping sections, thereby making it possible for said end flaps to be carried through said guiding means Without frictional drag; means mounted on said plate and moving in the same direction and at the speed of said conveyor for grasping and pulling said end flaps laterally to tighten said bags around articles limited as to transverse movement by the slotted sectionof said guiding means, said grasping and pulling means including a plurality of camactuated and positioned mechanical finger units; means mounted on said plate adjacent the clamping section of said guiding means for severing said end flaps and sealing said tightened bags simultaneously; and means for driving said conveyor, said guiding means, andsaid tightening means in the same direction at the same 7 speed.

'5. An automatic bag-tightening and sealing machine,

comprising: a conveyor for transporting loosely-fitted, article-containing bags having unfilled end flaps oriented in a direction transverse to the path of said conveyor;

a bag-tightening mechanism made up of an endless chain, means rotatably supporting said chain to form an elongated loop having a linear segment disposed adjacent said end flaps, a plurality of normally-closed mechanical finger units slidably coupled in transverse and spacedapart relation along the length of said endless chain, cams coupled to said rotatable supporting means for actuating said finger units into open position at one end of said linear segment to grasp saidend flaps, and to open said finger units at the other end of said linear segment to release said end flaps, another cam disposed opposite said linear segment to engage and slide said finger units away, from said conveyor to tighten said bags, and a further cam disposed in cooperative relation with another portion of said loop to engage and slide said finger units toward said conveyor into position for grasping said end flaps; an elongated thermal element disposed in the path of said end flaps following said linear segment for severing said flaps and sealing said bags: means disposed between said conveyor and said bag-tightening mechanism, and between said thermal element and said conveyor, for guiding said end flaps; and means coupled, respectively to said conveyor and said rotatable supporting means to produce movement of said conveyor and said linear segment in the same direction and'at the same speed.

6-. A bag-tightening and sealing machine comprising: a conveyor for translating loosely-fitted, article-containing plastic bags having end flaps oriented in the same direction transverse to the path of translation; first means disposed alongside said conveyor in the path of said end fiaps for grasping and pulling on said fiaps to tighten said bags; second means including an elongated thermal element disposed in the path of said end fiaps following said first means for severing said end flaps and sealing the severed edges of said bag; third means disposed in the path of said end fiaps between said conveyor and said first means and between said conveyor and said second means for guiding said end flaps; and means for driving said conveyor and said first means.

7. An automatic bag-tightening and sealing machine comprising: an endless, horizontal-surface conveyor for transporting plastic bags containing articles and having unfilled end flaps extending laterally in the same direction with respect to the direction of motion; a flap guide disposed along the edge of said conveyor nearest said flaps, said flap guide being made up of first and second upper guide plates adjustably mounted in end-to-end relation whereby the respective lower edges of said guide plates are colinear and effectively parallel to the surface of said conveyor, a first lower guide plate mounted below said first upper guide plate so that the upper edge of the former is spaced from the lower edge of the latter to form a slotted guide section of determinable slot width, and a series of lower guide plates having straight upper edges disposed in end-to-end relation below said second upper guide plate, and means for resiliently mounting each of said series of plates to exert an upward bias against the lower edge of said second upper guide plate, thereby forming a clamping section of said flap guide; two endless metal bands; means for rotatably mounting said bands to form an upper loop having a lower segment in longitudinal and slidable relation with the lower edges of said upper guide plates and a lower loop having an upper segment in longitudinal and slidable relation with the upper edges of said lower guide plates; a bag-tightener mechanism mounted adjacent to the slotted section of said flap guide, said mechanism including an endless chain, first and second sprockets rotatably mounted in proximity to the entry and terminal ends of said slotted section for supporting said endless chain for movement along an elongated path having an upper segment opposite the slotted section of said flap guide, a plurality of fingers having grasping ends nearest said slotted section and slidably coupled to said chain in lateral and spaced-apart relation, a plurality of opposing fingers mounted pivotally on said fingers to form fingerpairs, a plurality of resilient elements in cooperative relation with said finger-pairs for biasing the latter in closed position, and a plurality of actuating pins normally projecting from and slidably passing through said fingers at locations between said pivotal mountings and said grasping ends whereby pressure applied to said projecting ends will overcome the closing bias of said resilient elements and cause said finger-pairs to open, first and second pinactuating cams coupled to said first and second sprockets, respectively, and having cylindrical surfaces for engaging and pushing against the projecting ends of said actuating pins to open said finger-pairs, a first lateral positioning cam supported between said sprockets and having a cam surface in cooperative relation with the grasping ends of said fingers while the latter are moving along the upper segment of the elongated chain path whereby said closed 15 finger-pairs are shifted transversely away from said slotted section, and a second lateral positioning-cam supported between said sprockets and having a cam surface in cooperative relation with the other ends of said fingers moving along the lower segment of the elongated chain path to thrust said finger-pairs reciprocally into grasping position nearer said slotter section whereby said open fingers may close to grasp flaps extending through said entry end of said slotted section in order to pull and tighten said bags as said finger-pairs are shifted laterally by said first positioning cam and release said flaps as said finger-pairs engage the surface of said second pin-actuating cam opposite the terminal end of the slotted section; an elongated thermal element having extremities adjustably mounted adjacent the clamping section of said flap guide whereby said thermal element crosses the line of travel of said flaps through said clamping section, thereby simultaneously fusing the sides of said plastic flaps to form a seal and severing the remainder of said flaps from said bag; and

means for driving said conveyor, said bag-tightener mechanism and said metal bands at the same speed.

8. In a bag-tightening and sealing machine including a conveyor for transporting loosely-fitted, article-containing plastic bags having end flaps oriented in the same direction transverse to the conveyor path, an elongated thermal element for trimming and sealing said bags, a bagtightener stage, said stage comprising: a plurality of normally-closed, mechanical finger units having grasping ends; means for mounting said finger units in spaced-apart relation for reciprocal motion of said grasping ends toward and away from said end flaps; means coupled to said mounting means for driving said finger units in the same direction and at the same speed as said end flaps; and means disposed in cooperative relation with said finger units to effect opening and positioning operations of said units, said efiecting means including a first cam for opening said finger units for grasping said end flaps, a second cam for reciprocating said units to pull on said flaps and tighten said bags, a third cam for opening said units to release said end fiaps, and a fourth cam for reciprocating said units in the opposite direction.

9. In a bag-tightening and sealing machine including a conveyor for transporting loosely-fitted, article-containing bags having unfilled end flaps oriented in the same direction with respect to the conveyor path and means for trimming and sealing said bags, at bag-tightener stage comprising: a plurality of mechanical finger units mounted in spaced-apart relation for linear movement in the direction of said conveyor and for reciprocal movement toward and away from said end flaps; means driving said finger units linearly at the same speed as said conveyor; means in cooperative relation with said finger units to cause said units to grasp and pull on said end flaps; and means disposed in the path of said end fiaps and between said conveyor and said bag-tightener stage to position said flaps and restrain said articles.

References Cited in the file of this patent UNITED STATES PATENTS 2,253,036 Kimple et al Aug. 19, 1941 2,741,885 Allison Apr. 17, 1956 2,913,863 Sylvester et al Nov. 24, 1959 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3 011 295 December 5; 1961' Kenneth Ca Brugger It is hereby certified that error appears in the above numbered 'pat ent requiring correction and that the said Letters Patent should read as corrected below.

Column 3 line 44, for "problem" read problems line 45 for "protecting" read protection column 4 line 34,, for "bag" read bags column 6, line 69 for "procket" read sprocket column 7, line 8 for "pltae" read plate line 42 after "75," insert respectively to prevent the upper and lower metal bands 45 and 46 line 66,, for "pressure" read pressed column 11, lines 17 and 18 strike out "for the table 13 to provide a supporting surface" Signed and sealed this 24th day of April 1962. I

(SEAL) Attest:

ESTON c. JOHNSON DAVID L. LADD Attesting Officer I Commissioner of Patents 

